Banks and constructing societies have elevated money Isa charges in current weeks however now the method has stalled, mentioned Anna Bowes, founding father of financial savings charge monitoring service Savings Champion. "That's disappointing as we get closer to the end of the tax year, but there are still some attractive rates available right now.”

Cash Isa rates could soon start falling instead after consumer price inflation dropped more than expected in February to just 3.4 percent.

Inflation could hit two percent as soon as next month, which would pile even more pressure on the Bank of England to cut base rates.

As soon as we get that first cut, savings rates will fall and probably beforehand as banks and building societies jump the gun.

Savers can put up to £20,000 in a cash Isa and there is no time to lose, Bowes added. “It feels like rates may have hit the peak now, so anyone looking to open an Isa for this tax year might want to get a move on.”

The good news is that savers are finally getting an inflation-busting return.

By choosing a fixed-rate cash Isa, they can lock into today’s rates for up to five years, no matter what happens to inflation and interest rates.

However, savers must be able to tie up their money for the full term of a fixed-rate bond, as there are penalties for early withdrawals.

Bowes said a whole "gang" of providers offer one-year fixed rate bonds paying just over five percent, led by OakNorth and Kent Reliance who both pay 5.07 percent, with Paragon and Aldermore paying 5.05 percent.

“Virgin Money beats them all by paying 5.25 percent, but only if you have its current account, or open one.”

As always, check the minimum deposit, as this can vary. For example, OakNorth’s minimum is just £1, but that rises to £500 with Paragon and £1,000 with both Kent Reliance and Aldermore.

The longer the fixed rate, the less interest you get. For example, Skipton Building Society offers an 18-month fix paying 4.75 percent, while OakNorth and Close Brothers pay 4.70 percent for two years.

Over three years, Aldermore pays 4.50 percent, although Close Brothers has increased its rate to 4.40 percent.

Inevitably, five-year bonds pay less, with UBL paying 4.16 percent followed by Close Brother’s 4.15 percent.

Most of these rates can only be accessed online or via mobile savings app, but Skipton allows savers to open their account by post, telephone or branch, while UBL offers postal opening.

Those uncomfortable saving online should checking what their local building society offers, if they have a local branch. They often combine attractive rates with a more personal service.

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The high street banks rarely trouble the best buy tables but may tempt those lucky enough to still have a local branch. The Barclays 1-Year Flexible Cash Isa pays a fixed rate of 4.6 percent.

Savers who want easy access to their money rather than locking it away can get variable rates of more than five percent, but these will fall when interest rates are cut.

The Moneybox Cash Isa now pays 5.11 percent, leapfrogging Chip whose cash Isa was previously topping the best buy table paying 5.10 percent. Zopa, Virgin and Charter Savings Bank also pay more than five percent.

These are brilliant rates but may not last much longer, Bowes. "This could possibly be your final probability."

Today’s highest paying easy accessibility Isa really beats the most effective non-Isa model, Cynergy Bank’s 5.10 p.c charge, Bowes added.

This is nice news for savers with bigger sums in customary financial savings accounts, who threat exceeding their private financial savings allowance and paying tax on their curiosity.

Just do not go away it too lengthy. If inflation does fall to 2 p.c subsequent month, charges on money Isas and customary financial savings accounts will fall, presumably at velocity.